Cartridge case



March 27, 1962 D. METZGER 3,026,803

CARTRIDGE CASE Filed June 2, 1959 Fig.

Dan/'e/ Me/zger 1N VENTOR.

The present invention generally relates to an improved and novelcartridge case which may be constructed in any caliber and either centerfire or rim fire and involves certain safety features as well as a moreeffective cartridge case.

In present day construction, conventional cartridge cases quiteoften'malfunction due to what is commonly referred to as primer blow bacThe shoulder which abuts the inner end of the primer so constricts thepassage between the primer and the main portion of the shell that theforces created by the primer force the primer back out of the shell thuscausing the cylinder of the gun to jam and preventing rapid fire. Thiscondition is normally termed primer blow back and this is especiallytroublesome in firing wax projectiles by using the primer as theprojecting force. Therefore, it is the primary object of the presentinvention to provide a cartridge case in which there is a very smallshoulder for engaging the inner end of the primer thus leaving the holeat the inner end of the primer at the maximum diameter or size forreducing the restriction and reducing the tendency of the primer to blowback from the cartridge.

Another object of the present invention is to provide a cartridge caseconstructed of plastic in which the shoulder which limits the insectionof the primer melts away when the primer is fired thereby preventingreuse of the cartridge since the primer will not be held in the primerhole if the shoulder is missing thereby providing a safety feature sincea new cartridge must be used each time.

A further object of the present invention is to provide a plasticcartridge case which will be extremely inexpensive to manufacture andwill be a throw away item in that once it has been fired, it cannot beused and will be thrown away although the thin shoulder concept may beemployed in brass cartridges using regular powder and lead projectiles.

Another important object of the present invention is to provide acartridge case constructed of plastic in which the entrance to theprimer area is chamfered or tapered to assist the primer when it isbeing forced in place which construction enables the primer to be placedin firing po* sition just by using thumb pressure which is aninexpensive way for the individual to apply primers and it is furtherimpossible to apply enough force to the primer with your thumb to set itoff thereby providing another safety feature for those whose load theirown cartridges.

Still another feature of the present invention is the provision of acartridge case in which the primer hole is provided with serrationswhich, due to their plastic construction, are sufiiciently resilientthat they move outwardly when the primer is forced into the primer holeand thus securely grip the primer in position which also enables theprimer to be inserted by thumb pressure and once the primer is in place,the serrations grip the primer to prevent primer blow back.

Other objects of the present invention will reside in its extremesimplicity of construction, ease of loading the case by hand and itsinexpensive cost to enable the cartridges to be thrown away after oneuse.

These together with other objects and advantages which will becomesubsequently apparent reside in the details of construction andoperation as more fully hereinafter Patented Mar. 27, 1962 described andclaimed, reference being had to the accompanying drawings forming a parthereof, wherein like numerals refer to like parts throughout, and inwhich:

FIGURE 1 is a perspective view of the cartridge case of the presentinvention;

FIGURE 2 is a vertical sectional view taken substantially upon the planepassing along section line 22 of FIGURE 1 illustrating the details ofconstruction of the case; and

FIGURE 3 is a bottom plan view of the cartridge case taken substantiallyupon reference line 3-3 of FIG- URE 2.

Referring now specifically to the drawings, the numeral 10 generallydesignates the cartridge case of the present invention which includes acylindrical wall 12 having a peripheral flange 14 at the bottom edgethereof together with a projectile (not shown) forming the nose of thewall 12. The flange 14 is the usual construction for reception in thebreech of a gun such as in the cylinder of a revolver and which will beassociated with an extractor or ejector for operation in the usualmanner.

The end of the wall 12 having the flange 14 thereon is thickened intosubstantially an annular body 16 having an arcuate curved upper surface18 defining an opening 20 at the upper end of the primer hole 22. Aperipheral downwardly facing shoulder 24 is provided which forms anabutment for the primer (not shown). The lower end of the primer hole 22is tapered or outwardly chamfered as indicated by numeral 26 for forminga guide to assist the primer (not shown) when inserting the primer intothe primer hole 22. Also, the primer hole 22 is provided with aplurality of longitudinal serrations 28 therein for gripping engagementwith the primer (not shown) when inserted into the primer hole 22 intoabutting engagement with the shoulder 24.

While dimensions may vary as to the caliber, the following dimensionshave been found suitable for a 45 caliber cartridge. The over-all lengthis 1.030 inches, the thickness of the wall 12 tapering from .030adjacent the body 16 to the outer end of .025 inch thickness. Theserrations are .005 inch deep and the inside diameter of the serrationsis .210 inch. The inside diameter of the opening 20 is .170 inch whilethe shoulder is .125 inch in diametrical distance. The outside diameterof the outer end of the wall 12 is .475 while the outside diameteradjacent the body or at the body is .476 inch and the joint between thecurve 18 and the wall 12 is rounded to a .060 inch radius and thechamfer or taper is substantially 45.

Thus, when the primer is forced into the primer hole, the chamfer willassist the guiding of the primer into the primer hole and the serrationswill resiliently be forced outwardly for enabling thumb pressure toplace the primer in position thereby assuring that suflicient pressurewill not be placed on the primer to set 01f the primer or fire theprimer thereby providing a safety factor. When the primer is fired andthe wax projectile or some other type of projectile is projected fromthe cylindrical wall 12, the shoulder 24 will be melted 01f therebypreventing reuse of the cartridge, since the primer would then fall intothe interior of the cartridge if forced into the primer hole.

The foregoing is considered as illustrative only of the principles ofthe invention. Further, since numerous modifications and changes willreadily occur to those skilled in the art, it is not desired to limitthe invention to the exact construction and operation shown anddescribed and accordingly all suitable modifications and equivalents maybe resorted to, falling within the scope of the invention as claimed.

What is claimed as new is as follows:

A cartridge case comprising an elongated cylindrical wall, a flange atthe lower end of said wall projecting out- 3 wardly peripherallythereof, a thickened body portion at the flange end of said wall withthe wall having substantially a constant outside diameter from theflange to the opposite end, said thickened body portion having asmoothly curved convex inner surface extending inwardly and defining anorifice spaced from the flange end of the cartridge, a primer holeformed in 'the'fiange end of the cartridge and communicating with saidorifice, said primer hole having a diameter slightly larger than theorifice thereby providing a longitudinally outwardly facing shoulder forlimiting the insertion of aprimer into the primer hole, the diametricaldistance of the shoulder being relatively small in relation to'thediametrical distance of the orifice thereby forming but very littlerestriction of flow of gases from the primer into the cylindrical wallof the cart-ridge, said curved inner surface of the thickened bodyportion being continuous to said shoulder thereby defining a relativelythin lip forming said shoulder, said cartridge case being constructed ofplastic material whereby the thin lip forming the shoulder will meltwhen the primer is fired thereby preventing reuse of the cartridge case,said primer hole being chamfered at the outer end and provided with 4 aplurality of longitudinal serrations for grippingly engaging a smoothsurface primer when forced therein and enabling the primer to be forcedin the primer hole with only finger pressure exerted thereby preventingpressure on the primer duringinsertion thereof from firing the same andsecurely gripping the primer to prevent primer blow back when the primeris fired, said serrations including a plurality of longitudinal ridgesand depressions formed in the wall of the primer hole, the peaks of theridges being substantially in alignment with the inner edge of theshoulder with the bottoms of the depressions spaced slightly radiallyoutwardly from the inner edge of the shoulders thus further reducing thearea of the lip actually engaging the primer when inserted into theprimer hole.

